For those who aren't regular viewers of Jimmy Fallon's shows (previously Late Night, now his brand new The Tonight Show), one of the host's go-to skits involves inviting musicians to perform their hit songs—but swapping out guitars, pianos, and the like for classroom instruments. Last night, Idina Menzel was game for the challenge: Fresh off of her Oscars win, she, Fallon, and The Roots gave Frozen's "Let It Go" the classroom treatment, and Menzel's flawless voice (seriously!) was accompanied by xylophone, triangle, building blocks (?), and...a lemon, apparently. See how it all came together: